/* Modern CSS Reset and Base Styles */
*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

:root {
  /* Vietnamese-inspired Color Palette */
  --primary-gold: #D4AF37;
  --warm-gold: #F4E4BC;
  --deep-red: #C8102E;
  --forest-green: #228B22;
  --fresh-green: #90EE90;
  --rich-brown: #8B4513;
  --warm-cream: #FFF8DC;
  --soft-beige: #F5F5DC;

  /* Modern Neutral Colors */
  --white: #FFFFFF;
  --gray-50: #FAFAFA;
  --gray-100: #F4F4F5;
  --gray-200: #E4E4E7;
  --gray-300: #D4D4D8;
  --gray-400: #A1A1AA;
  --gray-500: #71717A;
  --gray-600: #52525B;
  --gray-700: #3F3F46;
  --gray-800: #27272A;
  --gray-900: #18181B;

  /* Typography */
  --font-primary: 'Inter', system-ui, -apple-system, sans-serif;
  --font-display: 'Playfair Display', serif;

  /* Spacing */
  --space-xs: 0.25rem;
  --space-sm: 0.5rem;
  --space-md: 1rem;
  --space-lg: 1.5rem;
  --space-xl: 2rem;
  --space-2xl: 3rem;
  --space-3xl: 4rem;

  /* Border Radius */
  --radius-sm: 0.375rem;
  --radius-md: 0.5rem;
  --radius-lg: 0.75rem;
  --radius-xl: 1rem;

  /* Shadows */
  --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
  --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
  --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
  --shadow-xl: 0 20px 25px -5px rgb(0 0 0 / 0.1), 0 8px 10px -6px rgb(0 0 0 / 0.1);

  /* Animations */
  --transition-fast: 150ms ease-in-out;
  --transition-normal: 250ms ease-in-out;
  --transition-slow: 350ms ease-in-out;
}

/* Base Styles */
html {
  scroll-behavior: smooth;
  text-size-adjust: 100%;
}

body {
  font-family: var(--font-primary);
  line-height: 1.6;
  color: var(--gray-800);
  background: linear-gradient(135deg, var(--warm-cream) 0%, var(--soft-beige) 100%);
  min-height: 100vh;
  font-feature-settings: 'rlig' 1, 'calt' 1;
}

/* Container */
.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--space-md);
}

/* Hero Section */
.hero-section {
  text-align: center;
  padding: var(--space-3xl) 0 var(--space-2xl);
  background: linear-gradient(135deg, var(--primary-gold) 0%, var(--warm-gold) 100%);
  border-radius: 0 0 var(--radius-xl) var(--radius-xl);
  margin-bottom: var(--space-2xl);
  position: relative;
  overflow: hidden;
}

.hero-section::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: url('data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 100 100"><defs><pattern id="grain" width="100" height="100" patternUnits="userSpaceOnUse"><circle cx="20" cy="20" r="1" fill="%23D4AF37" opacity="0.1"/><circle cx="80" cy="80" r="1" fill="%23D4AF37" opacity="0.1"/><circle cx="40" cy="60" r="1" fill="%23D4AF37" opacity="0.1"/></pattern></defs><rect width="100" height="100" fill="url(%23grain)"/></svg>') repeat;
  pointer-events: none;
}

.hero-content {
  position: relative;
  z-index: 1;
}

.hero-title {
  font-family: var(--font-display);
  font-size: clamp(2.5rem, 5vw, 4rem);
  font-weight: 600;
  margin-bottom: var(--space-md);
  color: var(--gray-900);
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-md);
}

.title-icon {
  font-size: 1.2em;
  filter: drop-shadow(0 2px 4px rgba(0, 0, 0, 0.2));
}

.hero-subtitle {
  font-size: 1.25rem;
  color: var(--gray-700);
  margin-bottom: var(--space-xl);
  font-weight: 400;
}

.hero-decoration {
  display: flex;
  justify-content: center;
  gap: var(--space-lg);
  margin-top: var(--space-lg);
}

.decoration-element {
  font-size: 1.5rem;
  opacity: 0.7;
  animation: float 3s ease-in-out infinite;
}

.decoration-element:nth-child(2) {
  animation-delay: 1s;
}

.decoration-element:nth-child(3) {
  animation-delay: 2s;
}

@keyframes float {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(-10px); }
}

/* Calculator Section */
.calculator-section {
  margin-bottom: var(--space-3xl);
}

.calculator-card {
  background: var(--white);
  border-radius: var(--radius-xl);
  padding: var(--space-2xl);
  box-shadow: var(--shadow-lg);
  border: 1px solid var(--gray-200);
  margin-bottom: var(--space-xl);
  position: relative;
  overflow: hidden;
}

.calculator-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 4px;
  background: linear-gradient(90deg, var(--primary-gold), var(--deep-red), var(--forest-green));
}

.calculator-header {
  text-align: center;
  margin-bottom: var(--space-xl);
}

.calculator-header h2 {
  font-family: var(--font-display);
  font-size: 2rem;
  font-weight: 500;
  color: var(--gray-900);
  margin-bottom: var(--space-sm);
}

.calculator-header p {
  color: var(--gray-600);
  font-size: 1.1rem;
}

/* Advanced Toggle */
.advanced-toggle-container {
  margin-top: var(--space-lg);
  display: flex;
  justify-content: center;
}

.toggle-switch {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  cursor: pointer;
  font-size: 0.9rem;
  color: var(--gray-600);
  transition: color var(--transition-normal);
}

.toggle-switch:hover {
  color: var(--gray-800);
}

.toggle-switch input[type="checkbox"] {
  display: none;
}

.toggle-slider {
  width: 44px;
  height: 24px;
  background: var(--gray-300);
  border-radius: 12px;
  position: relative;
  transition: background var(--transition-normal);
}

.toggle-slider::before {
  content: '';
  position: absolute;
  width: 20px;
  height: 20px;
  border-radius: 50%;
  background: var(--white);
  top: 2px;
  left: 2px;
  transition: transform var(--transition-normal);
  box-shadow: var(--shadow-sm);
}

.toggle-switch input:checked + .toggle-slider {
  background: var(--primary-gold);
}

.toggle-switch input:checked + .toggle-slider::before {
  transform: translateX(20px);
}

/* Input Section */
.input-section {
  max-width: 400px;
  margin: 0 auto;
  display: grid;
  gap: var(--space-lg);
}

.input-group {
  display: grid;
  gap: var(--space-sm);
}

.input-group.hidden {
  opacity: 0;
  max-height: 0;
  overflow: hidden;
  margin: 0;
  transition: all var(--transition-slow);
}

/* Advanced Inputs */
.advanced-inputs {
  opacity: 0;
  max-height: 0;
  overflow: hidden;
}

.advanced-inputs.visible {
  opacity: 1;
  max-height: 400px;
}

.advanced-inputs-grid {
  display: grid;
  grid-template-columns: 1fr 1fr 1fr;
  gap: var(--space-md);
}

@media (max-width: 640px) {
  .advanced-inputs-grid {
    grid-template-columns: 1fr;
    gap: var(--space-lg);
  }

  .input-section {
    max-width: 100%;
    padding: 0 var(--space-md);
  }

  .people-input {
    min-width: 0;
    font-size: 1rem;
    padding: var(--space-md) var(--space-lg);
    width: 100%;
  }

  .advanced-inputs.visible {
    max-height: 500px;
  }
}

@media (min-width: 641px) and (max-width: 768px) {
  .advanced-inputs-grid {
    grid-template-columns: 1fr 1fr;
  }
}

.input-label {
  font-weight: 500;
  color: var(--gray-700);
  font-size: 0.95rem;
}

.input-wrapper {
  position: relative;
}

.people-input {
  width: 100%;
  padding: var(--space-md) var(--space-lg);
  padding-right: 3rem;
  border: 2px solid var(--gray-300);
  border-radius: var(--radius-lg);
  font-size: 1.1rem;
  font-family: var(--font-primary);
  transition: all var(--transition-normal);
  background: var(--white);
}

.people-input:focus {
  outline: none;
  border-color: var(--primary-gold);
  box-shadow: 0 0 0 3px rgba(212, 175, 55, 0.1);
}

.people-input.invalid {
  border-color: var(--deep-red);
  box-shadow: 0 0 0 3px rgba(200, 16, 46, 0.1);
}

.input-icon {
  position: absolute;
  right: var(--space-md);
  top: 50%;
  transform: translateY(-50%);
  font-size: 1.2rem;
  pointer-events: none;
}

/* Calculate Button */
.calculate-button {
  width: 100%;
  padding: var(--space-lg) var(--space-xl);
  background: linear-gradient(135deg, var(--primary-gold) 0%, #B8941F 100%);
  color: var(--white);
  border: none;
  border-radius: var(--radius-lg);
  font-size: 1.1rem;
  font-weight: 500;
  font-family: var(--font-primary);
  cursor: pointer;
  transition: all var(--transition-normal);
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-sm);
  box-shadow: var(--shadow-md);
  position: relative;
  overflow: hidden;
}

.calculate-button::before {
  content: '';
  position: absolute;
  top: 0;
  left: -100%;
  width: 100%;
  height: 100%;
  background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.3), transparent);
  transition: left var(--transition-slow);
}

.calculate-button:hover::before {
  left: 100%;
}

.calculate-button:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-xl);
}

.calculate-button:active {
  transform: translateY(0);
}

.calculate-button:disabled {
  background: var(--gray-400);
  cursor: not-allowed;
  transform: none;
  box-shadow: var(--shadow-sm);
}

.calculate-button:disabled::before {
  display: none;
}

/* Results Container */
.results-container {
  opacity: 0;
  transform: translateY(20px);
  transition: all var(--transition-slow);
  max-width: 800px;
  margin: 0 auto;
}

.results-container.visible {
  opacity: 1;
  transform: translateY(0);
}

.results-header {
  text-align: center;
  margin-bottom: var(--space-xl);
}

.results-header h2 {
  font-family: var(--font-display);
  font-size: 2rem;
  color: var(--gray-900);
  margin-bottom: var(--space-sm);
}

.results-subtitle {
  color: var(--gray-600);
  font-size: 1.1rem;
}

/* Serving Options */
.serving-options {
  display: grid;
  gap: var(--space-lg);
  margin-bottom: var(--space-2xl);
}

@media (min-width: 768px) {
  .serving-options {
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  }
}

.serving-card {
  background: var(--white);
  border-radius: var(--radius-lg);
  padding: var(--space-xl);
  box-shadow: var(--shadow-md);
  border: 1px solid var(--gray-200);
  transition: all var(--transition-normal);
  opacity: 0;
  transform: translateY(20px);
  position: relative;
  overflow: hidden;
}

.serving-card.animated {
  opacity: 1;
  transform: translateY(0);
}

.serving-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-xl);
}

.serving-card[data-type="appetizer"] {
  border-left: 4px solid var(--forest-green);
}

.serving-card[data-type="main meal"] {
  border-left: 4px solid var(--deep-red);
}

.serving-card[data-type="party/sharing"] {
  border-left: 4px solid var(--primary-gold);
}

.serving-icon {
  font-size: 2.5rem;
  margin-bottom: var(--space-md);
  text-align: center;
}

.serving-info h3 {
  font-family: var(--font-display);
  font-size: 1.5rem;
  color: var(--gray-900);
  margin-bottom: var(--space-sm);
}

.serving-description {
  color: var(--gray-600);
  margin-bottom: var(--space-lg);
  font-size: 0.95rem;
}

.serving-amount {
  text-align: center;
  margin-bottom: var(--space-md);
}

.roll-count {
  font-size: 3rem;
  font-weight: 700;
  color: var(--primary-gold);
  display: block;
  line-height: 1;
}

.roll-label {
  color: var(--gray-600);
  font-size: 0.9rem;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.per-person {
  text-align: center;
  color: var(--gray-500);
  font-size: 0.9rem;
  font-style: italic;
}

/* Cooking Tips */
.cooking-tips {
  background: linear-gradient(135deg, var(--fresh-green) 0%, #7FD67F 100%);
  border-radius: var(--radius-lg);
  padding: var(--space-xl);
  color: var(--gray-800);
}

.cooking-tips h3 {
  font-family: var(--font-display);
  font-size: 1.5rem;
  margin-bottom: var(--space-lg);
  color: var(--gray-900);
}

.cooking-tips ul {
  list-style: none;
  display: grid;
  gap: var(--space-md);
}

.cooking-tips li {
  display: flex;
  align-items: flex-start;
  gap: var(--space-sm);
}

.cooking-tips li::before {
  content: '✨';
  flex-shrink: 0;
  margin-top: 2px;
}

/* Info Section */
.info-section {
  margin-bottom: var(--space-3xl);
}

.info-grid {
  display: grid;
  gap: var(--space-xl);
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
}

.info-card {
  background: var(--white);
  border-radius: var(--radius-lg);
  padding: var(--space-xl);
  box-shadow: var(--shadow-md);
  border: 1px solid var(--gray-200);
  transition: all var(--transition-normal);
  text-align: center;
}

.info-card:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-lg);
}

.info-icon {
  font-size: 3rem;
  margin-bottom: var(--space-md);
}

.info-card h3 {
  font-family: var(--font-display);
  font-size: 1.25rem;
  color: var(--gray-900);
  margin-bottom: var(--space-md);
}

.info-card p {
  color: var(--gray-600);
  line-height: 1.6;
}

/* Footer */
.footer {
  background: var(--gray-800);
  color: var(--gray-300);
  text-align: center;
  padding: var(--space-xl) 0;
  border-radius: var(--radius-xl) var(--radius-xl) 0 0;
}

.footer-content p {
  margin-bottom: var(--space-sm);
}

.footer-note {
  font-size: 0.9rem;
  opacity: 0.8;
}

/* Error Message */
.error-message {
  background: linear-gradient(135deg, #FEE2E2 0%, #FECACA 100%);
  border: 1px solid #F87171;
  border-radius: var(--radius-lg);
  padding: var(--space-lg);
  text-align: center;
  color: var(--deep-red);
}

/* Image Styling */

/* Hero Background Image */
.hero-background {
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  overflow: hidden;
  border-radius: 0 0 var(--radius-xl) var(--radius-xl);
}

.hero-image {
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: center;
  opacity: 0.3;
  transition: opacity var(--transition-slow);
}

.hero-section:hover .hero-image {
  opacity: 0.4;
}

.hero-content {
  position: relative;
  z-index: 2;
}

/* Info Card Images */
.info-image-container {
  position: relative;
  width: 100%;
  height: 200px;
  border-radius: var(--radius-md) var(--radius-md) 0 0;
  overflow: hidden;
  margin-bottom: var(--space-md);
}

.info-image {
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: center;
  transition: transform var(--transition-normal);
}

.info-card:hover .info-image {
  transform: scale(1.05);
}

.info-icon-overlay {
  position: absolute;
  top: var(--space-md);
  right: var(--space-md);
  background: rgba(255, 255, 255, 0.9);
  backdrop-filter: blur(10px);
  border-radius: 50%;
  width: 48px;
  height: 48px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.5rem;
  box-shadow: var(--shadow-md);
}

/* Serving Card Images */
.serving-image-container {
  position: relative;
  width: 100%;
  height: 160px;
  border-radius: var(--radius-md) var(--radius-md) 0 0;
  overflow: hidden;
  margin-bottom: var(--space-md);
}

.serving-image {
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: center;
  transition: transform var(--transition-normal);
}

.serving-card:hover .serving-image {
  transform: scale(1.03);
}

.serving-icon-overlay {
  position: absolute;
  top: var(--space-sm);
  right: var(--space-sm);
  background: rgba(212, 175, 55, 0.9);
  backdrop-filter: blur(8px);
  border-radius: 50%;
  width: 40px;
  height: 40px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.2rem;
  color: white;
  text-shadow: 0 1px 2px rgba(0, 0, 0, 0.3);
  box-shadow: var(--shadow-sm);
}

/* Fallback styling for missing images */
.info-image,
.serving-image,
.hero-image {
  background: linear-gradient(135deg, var(--warm-gold) 0%, var(--primary-gold) 100%);
}

.info-image::before,
.serving-image::before {
  content: '🥢';
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  font-size: 3rem;
  opacity: 0.3;
}

/* Responsive Image Adjustments */
@media (max-width: 768px) {
  .info-image-container {
    height: 150px;
  }

  .serving-image-container {
    height: 120px;
  }

  .hero-image {
    opacity: 0.2;
  }
}

@media (max-width: 480px) {
  .info-image-container {
    height: 120px;
  }

  .serving-image-container {
    height: 100px;
  }

  .info-icon-overlay,
  .serving-icon-overlay {
    width: 36px;
    height: 36px;
    font-size: 1rem;
  }
}

/* Responsive Design */
@media (max-width: 768px) {
  .container {
    padding: 0 var(--space-sm);
  }

  .hero-title {
    font-size: 2.5rem;
    flex-direction: column;
    gap: var(--space-sm);
  }

  .calculator-card {
    padding: var(--space-lg);
  }

  .hero-decoration {
    gap: var(--space-md);
  }

  .decoration-element {
    font-size: 1.2rem;
  }
}

@media (max-width: 480px) {
  .hero-section {
    padding: var(--space-2xl) 0 var(--space-lg);
  }

  .calculator-header h2 {
    font-size: 1.5rem;
  }

  .info-grid {
    grid-template-columns: 1fr;
  }
}